Most Helpful Girl
People wear trendy clothes for a huge number of reasons.
Fashion is not all about the clothes and the makeup, but the excitement and energy that the industry gives off. You see, it’s not just “stuff". For some, it's a way of expressing themselves. It's a way of showing creativity, status, wealth. It has a cultural element too. People buy "tacky" (your words!) trendy, clothes to fit in, to give the impression that they are in the loop. Wearing clothes that are in style can make people feel good about themselves. In a way, wearing trendy clothes is almost like a test of a person's confidence - how well can they 'pull' off the look?
Maybe they wear tacky clothes to annoy some people (you, for example!). The fact that it annoys them is all the more reason to keep doing it.
At the end of the day though, we live in a consumer world. Shopping and spending money on fashionable clothes has become an integrated part of our lifestyle and culture!